What is the purpose of by-pass valves when used with larger valves?

By-pass valves serve a vital function in systems utilizing larger valves, particularly in managing the flow and temperature of the fluid in the piping system. When the main valve is closed or being operated, the by-pass valve allows for fluid to continue flowing, which helps to prevent thermal shock to downstream components.

Warming the downstream pipe before opening the main valve is crucial because it allows for a gradual adjustment of temperature and pressure in the system, reducing the risk of damage or stress that could occur from sudden changes. This is especially important in systems where fluids are heated or cooled rapidly, as sudden temperature changes can lead to issues like cracking or weakened joints.

In the context of maintaining operational efficiency, using a by-pass valve can ensure that the flow characteristics and conditions remain stable when the main valve is not in operation, thereby safeguarding the overall integrity of the system. This function greatly contributes to the reliability and longevity of the piping system, particularly in complex industrial settings where larger valves may be operating under significant pressure or temperature variations.